For average collapsible two-layer canopy wind resistant umbrellas shown in FIGS. 1 through 3 it is principally constructed by linking a pivoting element (a) of a main umbrella stretcher with a connection element (b) that accommodates a tail plate (c) to form a support stretcher. Such a structure only utilizes a combination between the connection element (b) and the tail plate (c) to withstand wind force. When wind blows, the tail plate (c) is lifted. The stretcher is easy to be bent or even broken because the force is exerted on the joint between the connection element (b) and the tail plate (c). In addition, the linkage between the tail plate (c) and the connection element (b) is only achieved by an obliquely projecting tab (d) and thus the connection is vulnerable and easy to be broken.
In view of the above-mentioned problems, the object of the invention is to provide an innovational stretcher structure used in collapsible two-layer canopy wind resistant umbrellas that has multiple support points to resist wind forces and provide effective restoring forces to prevent canopies and stretchers from being overturned or damaged. Now the features and structure of the present invention will be described in detail with reference to the concomitant drawings.